On Thu, 17 Jun 2010 16:19:43 +0300 (IDT)
Alexander Nezhinsky <alexandern@xxxxxxxxxxxx> wrote:
> When a numerical command line param value is out of range or contains garbage
> (both tgtd and tgtadm), this remains unchecked in many cases.
> In some of them 0 value will be used, which may lead to unpredicted or
> "silently" faulty behavior.
>
> This fix defines a new function str_to_uit64() which uses strtoull() and
> detects its errors properly, by checking 1) errno (range errors) and
> 2) comparing endptr to the original argument (nun-numerical garbage);
> must check both.
>
> str_to_uit64() is declared static twice, in tgtd.c and tgtadm.c, as
> tgtadm does not uses util.c, where the natural place of this function
> would be otherwise.
>
> It returns the converted integer value directly, while error is returned
> through a pointer argument. Although the opposite arrangement may seem
> intuitive, this one allows free casting of the returned value to various
> types. Return type uint64 is choosen to cover all possible cases.
> min and max arguments support range checking. To use the natural integer
> ranges, use ULLONG_MAX, ULONG_MAX, USHRT_MAX etc.
>
> Signed-off-by: Alexander Nezhinsky <alexandern@xxxxxxxxxxxx>
I'm for the strict checking however two comments.
- casting a returned value looks ugly.
- duplicating the same function isn't nice.
How about something like this?
diff --git a/usr/tgtadm.c b/usr/tgtadm.c
index 28ed754..2282c86 100644
--- a/usr/tgtadm.c
+++ b/usr/tgtadm.c
@@ -471,8 +471,8 @@ int main(int argc, char **argv)
mode = str_to_mode(optarg);
break;
case 't':
- tid = strtol(optarg, NULL, 10);
- if (errno == EINVAL) {
+ tid = str_to_val(optarg, int, 0, INT_MAX, &rc);
+ if (rc == EINVAL) {
eprintf("invalid tid '%s'\n", optarg);
exit(EINVAL);
}
diff --git a/usr/util.h b/usr/util.h
index 6e1fd6f..fc406b1 100644
--- a/usr/util.h
+++ b/usr/util.h
@@ -156,4 +156,17 @@ struct signalfd_siginfo {
};
#endif
+#define str_to_val(str, type, min, max, err_ptr) \
+({ \
+ char *ptr; \
+ int ret = 0; \
+ typeof(type) v = strtoull(str, &ptr, 0); \
+ if (errno || ptr == str) \
+ ret = EINVAL; \
+ if (v < min|| v > max) \
+ ret = ERANGE; \
+ *err_ptr = ret; \
+ v; \
+}) \
+
#endif
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